Resumen:

3-Methyl-l-phenyl-2-pyrazolin-5-one 1b and 1-dodecyl-3-methyl-2-pyrazolin- 5-one 1c react with carbon disulfide and 1,5-dibromopentane in the presence of sodium acetate in dimethylformamide or n-butyllithium in tetrahydrofuran to afford 1,5-bis(4-dithiocarboxylate-5-hydroy-pyrazolyl)pentane derivatives 6b-c.